And Customise It To The Death.
Yes, there are plenty of paths to take with these magic, so anyone can mix a cocktail of their own choosing. Let's see: (poles)
- the question of whether the 'poles' are pre-determined for a person, or can be changed
- if permanent, there can be a lasting distinction between certain groups of people - gender even. (Insert any number of butt jokes about those freaks that have their pole 'the other way around'.)
- or, the 'pole' of a person is randomly determined or chosen by a person in the course of her studies of magic.
- if it can be changed, how easy is it? And what impact will a change of the pole have on the casting skill of the adept? Is it just something to be determined at each spell anew; or are arduous exercises, or special rituals/potions needed to cause a change? Or can the caster be 'neutered' (voluntarily or not), and that choose anew? In short, is the pole just the switch you turn around as desired, or the very basis of the power, the potential you grow in yourself, much like that magnet example? At the very least, there has to be a little time spent on the change (roll for success in a tight situation).
- how will wizards of opposite/same poles react on each other? Will there be attraction, or repulsion? Will they feel each other (and will they feel a particular pole easier)?(availability)
- may be 'just another magical tradition'
- may be the only option to use magic for a whole setting, or a particular race (I like this one better)
- oh, right, it may be also a cultural thing
If the Polar magic seems a little clinical, remember the concepts of yin and yang and all the philosophical trappings attached to them - you can smuggle them here easily. If compared to other ways to magic, it can be simply claimed that all of them do it already, and create the poles in one or other way.
Then is there the question of power... if wizards are able to cast spells on their own, this whole concept turns just into a power upgrade if you have more wizards. For sure I would allow cantrips. But for all spells must be both poles present, and the more power is between them, the more danger for the magus maintaining the poles in his body. Cantrips would itch, weak spells mean pain, and anything more would create larger damage until some spectacular death slays you - like burning from the inside of your frozen skin.
The power to disrupt the casting of others, however, can definitely belong to every magic-user.
If you want system, you will get system.
Myself, I like point-based games where you compose your character's powers of skills - which would go well with this one. I see two basic options for a fast play:
- A set low diffilcuty for each spell, where _both_ casters have to have at least this required level of skill, or they can't participate. Most spells would be 'low-level' anyway, but for real stuff you need real men, I mean, wizards.
- For each spell a set high diffilcuty, where both casters add their skills together, and make one roll for success. The stronger caster can drag the weaker along.
Then there is the important question of fun. Notice that you either provide a large list of possible combined effects, or supply a few and let the players play (danger!
). You could easily go here for a more freeform/storytelling approach, creating effects based on their impact on the world, and the like. Can be lots of fun, but GM beware.